§ 4-18 Exterior Veneering Materials.
RCNY § 4-18
(a)Scope. These rules are supplementary and additional to the requirements pertaining to exterior veneering materials not exceeding 2" in thickness, so as to provide for the sufficiency of attaching and anchoring mediums on such exterior veneers in accordance with the intent of the Administrative Building Code as outlined in § C26-3.0. They shall apply to veneering materials of metal, cement-asbestos, precast or natural stone, marble, ceramic, tile, concrete masonry units, glass sheets, glass block, plastic materials and other veneering materials, as may be approved by the Board. Note: These rules shall not apply to interior veneering materials. Extracts from the Administrative Building Code contained herein in small type have been assigned decimal rule numbers for convenient reference only and are not to be construed as rules.
(b)General.
(1)These rules shall apply to all materials used as exterior veneers of a thickness not exceeding two inches, bonded or unbonded, and with or without air spaces between the veneer and the supporting surface.
(2)Veneer materials shall not be credited with contributing to the total wall thickness, the stress resisting sections, or to the fire resistive value of the composite construction unless specifically approved by the Board for any given combination of materials.
(3)Veneer materials shall not be used to support vertical loads other than the veneering material above unless permitted otherwise as provided for in 2 RCNY § 4-18(b)3(3). Where openings occur the veneer shall be supported by substantial lintels of incombustible materials.
(4)All joints between masonry veneer materials shall be filled flush with mortar or approved mastic cement. Around wall openings the joints between the veneer and backing material shall be filled flush with similar materials. Gypsum shall not be used in veneer exposed to the weather except for temporary tacking and supplementary to the anchorage and cement mortar requirements set forth in these rules.
(5)All rosettes, toggle or expansion belts, metal reinforcements, bolts, clips, tie wires and supports shall be of non-corroding metal and of a type and for uses as may be approved by the Board.
(6)Veneering material shall not be placed over existing veneering material.
(7)Veneering when placed on a structure shall not encroach beyond the building line.
(8)Before attaching veneering materials to any surface, the soundness of structural members shall be examined by exposing the structural members and when found necessary, reinforcement or replacement of structural members shall be made to the satisfaction of the borough superintendent.
(9)Signs shall be so hung that their weight shall not bear on the veneering material and shall be supported by grounds set in the supporting wall.
(10)Veneering materials used above the first floor shall be installed in a manner permitting Fire Department access to each floor by means of existing or new windows or readily accessible access panels installed as provided in § C26-550.1d.
(11)Where openings occur in a wall, the veneer shall be supported by a structural member of incombustible material.
(12)All masonry walls shall be cleaned of dust and dampened before stone, marble, precast concrete units, tile or terra cotta is applied.
(c)Metal veneers.
(d)Precast or natural stone, marble, structural clay, ceramic and porcelain tile, terra cotta and precast concrete units.
(ii)For anchorage of architectural terra cotta and other moulded units on masonry, one non-corroding metal anchor at least equal to five-sixteenths of an inch round or one-eighth of an inch by three-quarters of an inch flat in sectional area to each piece and two or more such anchors to all pieces over 18 inches in length or more than three hundred square inches in superficial area, except where such architectural terra cotta facing is bonded and completely filled with the brick backing.
(iii)For anchorage of stone veneering on masonry, one non-corroding anchor at least three-sixteenths of an inch by one inch flat, or its equivalent in cross sectional area, to each piece over one-half of a square foot in face area and at least two anchors to all pieces over 24 inches in length or more than four hundred square inches in superficial area.
(iv)Frame structures veneered with masonry shall be considered to be in a different class from masonry structures. It shall be unlawful to attribute any structural strength to the veneer.
(e)Glass veneer on the exterior of structures may be used only in accordance with the provisions of this title and the rule of the Board.
(i)The maximum area of a single section of glass veneer shall not exceed 10 sq. ft. in area when 15 ft. or less above the level of the sidewalk directly below shall not exceed 6 sq. ft. in area when more than 15 ft. above the level of the sidewalk directly below.
(v)Where glass veneer extends to the sidewalk surface each such section shall rest on two cushions of approved resilient material, one near the end of each such section or plate. Cushions shall be one-quarter of an inch or more in thickness. The joint between the bottom edge of the glass section and the top of the sidewalk shall be caulked with a waterproof compound.
(vi)Where the glass veneer is permitted to extend below the level of the sidewalk surface, an expansion joint of one-quarter of an inch or more shall be provided between the outer face of the glass veneer and the edge of the sidewalk. Such expansion joint space shall be filled with a resilient caulking compound from the level of the sidewalk surface to a depth at least 3/4 of an inch below such level.
(vii)Where glass veneer is applied at an elevation more than eight feet above the sidewalk surface, the mastic cement binding shall be supplemented by the use of metal clip angles of a design approved by the Board. Clips shall be located in each vertical or horizontal edge of each section of veneer and shall be secured through the backing directly into the wall behind by means of expansion bolts and in a manner satisfactory to the superintendent. Angle clips shall be two inches or more in length and shall be of at least No. 16 U.S. gauge, and shall be so designed as to furnish at least two-inch bearing support on each clip and shall hold the glass in a vertical plane independently of the mastic cement.
(viii)All horizontal joints shall be cushioned with pads of adhesive asphaltic tape which shall extend from the rear surface of the glass to one-eighth of an inch or less from the front surface. Horizontal joints shall be buttered with joint cement over the full depth of the joint, including the surface of the cushion tape.
(ix)Shelf angles of approved design shall be set at vertical intervals of 3 ft. or less, in all horizontal joints located 8 ft. or less above the sidewalk, except that, where there are show windows it shall be unnecessary to have shelf angles below the level of the tops of the show window bulkheads. Shelf angles shall be of a type approved by the board and shall be secured to the backing in a manner satisfactory to the superintendent.
(x)Where glass veneer is confined between non-resilient materials at ends, expansion shall be provided for by means of an expansion joint at each end of one-quarter of an inch or more throughout the entire height of the veneer.
(f)Glass blocks (§ C26-550.1j.). Veneer or ashlar: Glass blocks may be used as exterior wall veneer under the rules of the Board. Note: Investigation has shown that glass block is not used as a veneer material in building construction and when uses of glass block are developed as veneer, the Board will then consider including in these rules the safe provisions for use.
(g)Veneering units of a type unprovided for in these rules, may be used, provided they are approved by the Board and are used in accordance with the limitations of the approval. (Renumbered City Record 4/4/2019, eff. 5/5/2019)
